Continuous flow counter-current liquid and solid contact apparatus

ABSTRACT

A counter-current liquid and solids continuous contact apparatus comprises a trough for flowing the liquid in one direction and a helical arrangement of paddles for tumbling and advancing the solids in the opposite direction upstream. The paddles include flat vanes for advancing the solids and curved scoops for tumbling the solids, the coaction between the vanes and the scoops being such as to provide greatly enhanced large area contact between the liquid and the solids.

United States Patent [19 Gill et al.

[ CONTINUOUS FLOW COUNTER-CURRENT LIQUID AND SOLID CONTACT APPARATUS[75] Inventors: William N. Gill, Eggertsville',

Mahendra R. Doshi, Buffalo, both of N.Y.; Robert E. Adams, Topsfield,

Mass.

[73] Assignee: J. W. Greer, lnc., Wilmington,

Mass.

[22] Filed: Feb. 8, 1973 [21] Appl. No.: 330,888

[52] US. Cl. .1 134/60; 134/65; 134/66; 23/270 R; 259/9; 259/104;416/175 [51] Int. Cl. B081) 3/08 [58] Field of Search 134/65, 132, 60,66; 23/270 R; 259/9, 10, 104; 127/57; 416/124,

[56] References Cited UNITED STATES PATENTS 34,770 Palmer .1 416/175 [41 July 22, 1975 266,011 10/1882 Blackman 416/203 X 1,866,030 7/1932Green l 1 23/270 R 2,238,690 4/1941 Fell l l 134/65 X 2,698,742 1/1955McCoy l A l 259/9 X 3,297,043 1/1967 Adams .1 134/65 X PrimaryExaminerRobert L. Bleutge Attorney, Agent, or FirmMorse, Altman, Oates &Bello 1 1 ABSTRACT A counter-current liquid and solids continuouscontact apparatus comprises a trough for flowing the liquid in onedirection and a helical arrangement of paddles for tumbling andadvancing the solids in the opposite direction upstream The paddlesinclude flat vanes for advancing the solids and curved scoops fortumbling the solids, the coaction between the vanes and the scoops beingsuch as to provide greatly en hanced large area contact between theliquid and the solids.

8 Claims, 9 Drawing Figures SHEET PATENTED JUL 2 2 ms SHEET PATENTEDJUL22 ms FIG. 4

PATENTED JUL 22 I975 FIG. 6

1] 4-LIQUIDS IN LOW LEVEL DISCHARGE HIGH LEVEL DISCHARGE FIG. 8

CONTINUOUS FLOW COUNTER-CURRENT LIQUID AND SOLID CONTACT APPARATUSBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to counter-current liquid and solids continuous contactapparatus, commonly called a counter-current contactor, and, moreparticularly to a horizontal counter-current contactor which providescontinuous, liquid-solid contact for extracting, leaching, ion exchange,decoloring, deodorizing, crystallizing, washing, flotation and the like.

2. The Prior Art In counter-current contactors, it has been proposed toprovide adjustable paddles arranged to form an interrupted helix, thepaddles slowly lifting the solid material from a trough, tumbling itgently, and advancing it upstream continuously counter to the directionof liquid flow. The purposes of such a contactor are as follows: itallows continuous operation without down time for repacking columns,flushing, or regenerating; continuous counter-current flow eliminatesstart-of-run and end-of-run differences and allows controlled uniformeffluent; samples or side streams of liquid or solid material or bothmay be removed or introduced at selected points; gentle lubricated"tumbling of solids minimizes or eliminates attrition of valuable solidssuch as ion exchange resin beads; the contactor may be jacketed for heattransfer, if desired; troughs can be rubberlined, if desired; forcertain applications wipers may be added to the paddles to provide acontinuous selfcleaning action. In such apparatus difficulties have beenencountered in achieving the desired intimate contact between the liquidand solids.

SUMMARY OF THE INVENTION The object of the present invention is toprovide a counter-current liquid and solids continuous contact apparatuscharacterized by a trough for flowing the liquid in one direction and ahelical arrangement of paddles for tumbling and advancing the solids inthe opposite direction upstream, the paddles including generally flatvanes for advancing the solids and generally curved scoops for tumblingthe solids. It has been found that the coaction between the vanes andthe scoops is such as to provide greatly enhanced large area contactbetween the liquid and the solids. The apparatus of the presentinvention has been found particularly efficacious in ion exchangereactions.

Other objects of the present invention will in part be obvious and willin part appear hereinafter.

The invention accordingly comprises the apparatus, its components andtheir interrelationships, as illustrated in the present disclosure, thescope of which will be indicated in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of thenature and objects of the present invention, reference is made to thefollowing detailed description, taken in connection with theaccompanying drawings, wherein:

FIG. 1 is a side view, with portions broken away, of a portion of anapparatus embodying the present invention;

FIG. 2 is an end view of the portion of FIG. 1;

FIG. 3 is a top plan view of the entire apparatus of FIG. 1;

DESCRIPTION OF A PREFERRED EMBODIMENT In the drawings, the numeraldesignates a single independent unit of a counter-current contactorembodying the present invention. Unit 20 is supported at v a desiredelevation on a suitable supporting framework or leg structure (notshown).

Unit 20 includes three (or more) parallel elongated U-shaped troughs 21,22 and 23, which are of equal length and which extend substantially forthe entire length of the unit 20. The vertical side walls 24 of thethree troughs are all of the same height and the two outermost troughs21 and 23 have outer side walls 25 which extend above the tops of sidewalls 24. The outermost side walls 25 are strengthened by a series ofcrossbraces 26 interconnected with longitudinal bars or braces 27. Anyalternate structure may be employed to render the shell of unit 20sufficiently rigid, the shell being formed of sheet metal. Unit 20 alsomay embody an underlying casing or housing 28 below the bottoms oftroughs 21, 22 and 23.

Within each trough 21, 22 and 23 and extending lengthwise and centrallytherein for the entire length thereof is a rotary hollow shaft 29,having secured thereto adjustably a plurality of radially extendingpaddles 30 and scoops 31, which collectively are disposed along aninterrupted helix. As will be explained, paddles 30 advance solids alongthe trough and scoops 3l lift solids from the bottom of the trough,tumble it gently, and advance it upstream counter to the flow of liquidthrough the trough. The liquid moves by hydraulic gradient, notrequiring a pressure feed.

Each paddle 30 is a flat plate element having outwardly diverging sideedges and a circularly curved outer peripheral edge. Each scoop has acylindrically curved catch portion that is semi-circular in crosssection and a flat inner face, defining a region with open top and openouter end. Each paddle and scoop pair are rigidly anchored to anadjusting rod 33 which in turn is connected to rotary shaft 29 by meansof adjustable screw-threaded parts 34 or the like. Other forms ofconnections between the paddle and scoop pairs and shaft 29 may beemployed. In any event, each paddle and each scoop may have its pitch orangle changed with reference to shaft 29. This adjustability enablesaccurate setting to lift various solids from the bottom of the troughand to advance them along. Some solids behave differently from othersand the adjustability feature is therefore necessary. Paddles 30 alsoare set to overlap longitudinally of shaft 29 so that the solids aregently tumbled by the scoops in maximum contact with the counter flowingliquid. The arrangement of the several pairs of paddles and scoops basicin allowing the liquid to flow by gravity reversely to the advancementof the solids through the liquid stream. Intimate contact of the solidswith the liquid is obtained without restricting liquid flow.

The end portions of the three shafts 29 are supported exteriorly of theend walls 35 and 36 of the multiple trough structure by means of sturdybearings 37 which may be bracketed to the end walls or suitably tied into the underlying supporting frame structure, not shown. This outboardarrangements of bearings relieves the sheet metal trough structure fromthe direct support of shafts 29.

As shown in FIG. 3, the three shafts are geared together at 38 and 39 toturn in unison and in the same direction. One shaft may be powered bysuitable gearing 40, driven by an underlying variable speed drive (notshown). Unit may be of any practical length.

The diagram in FIG. 7 shows the essential paths of solids and liquidsthrough the basic unit 20 of the apparatus. The path of the solids isindicated by solid line 41 and the path of the liquid by broken line 42,the diagram illustrating the counter flow of the liquid and solidsthrough the three troughs 21, 22 and 23. With continued reference toFIG. 7, there is shown diagrammatically a solids outlet 43 at one end oftrough 21. At the remote end of trough 23 is a liquid outlet 44. Solidsare introduced into the system slightly upstream from the outlet 44.There are two additional points in unit 20, indicated at 45, 46, wheresolids are transferred from one trough to the next without interferingwith the counter flow of liquid. The structures shown particu' larly inFIGS. 1, 4 and 6 provide for these transfers of solids and/or liquidfrom trough to trough.

FIG. 4 shows the three troughs 21, 22 and 23 and associated elements incross section adjacent liquid outlet 44. At liquid outlet 44, adischarge receptacle 47 or the like is provided upon the outer side oftrough 23 at one end thereof. A vertically adjustable weir 48 isprovided to regulate the outflow of liquid from the trough 23 into thereceptacle 47, and this weir also controls the liquid level in theentire system, i.e. in the three troughs of unit 20. It may be observedin FIG. 3 that paddles 30 in each trough 21, 22 and 23 are properlypitched to cause advancing of the solids in the direction of flow, asindicated in FIG. 7 by the solid line, when the several shafts 29 areturning in the direction indicated in FIG. 4. The liquid in the systemof course flows in the opposite direction as previously explained.

The previously mentioned transfer point 45 for solids and liquidsbetween troughs 21 and 22 also is shown in FIG. 4. Means are provided atthis point to transfer solids from the trough 22 to the trough 21,without interrupting the counter flow of liquid from the trough 21 tothe trough 22. This means comprises a scoop 49 having a tubular hub 50cross-bolted rigidly to shaft 29 as at 51. Scoop 49 therefore turns withshaft 29 in trough 22. Scoop 49 comprises diametrically opposedreversely curved blades 52, whose tips 53 pass close to the wall oftrough 22. The scoop also has side wall portions 54 integral therewith,in turn having outwardly flared terminal straight edge portions 55 forclose contact with a coacting scavenger plate or scraper 56. Scavengerplate 56 has its upper end pivoted at 57 between a pair of thetransverse braces 26 and has a bottom transverse lip 58 which rests uponthe scoop blades 52 to scrape and transfer solids therefrom into thetrough 21 during rotation of the shaft 29 in the trough 22. Scavengerplate 56 is freely suspended under the influence of gravity and merelyrises and falls by the camming influence of rotating blades 52.

To effect the actual transfer of solids and liquid between troughs 22and 21, the adjacent side walls 24 are notched as at 59. This forms ahorizontal edge 60 of reduced height over which the liquid can flowreadily from trough 21 to trough 22 and this edge is well below the topedge of the liquid outlet weir 48. Rotating scoop 49, coacting withscavenger plate 56, elevates and smoothly transfers solids from thetrough 22 to the trough 21 and over edge 60 in the reverse direction toliquid flow. Scavenger plate 56 with lip 58 continuously scrapes thesolids from the two sections of the scoop and forces them through thenotch between the two troughs and into trough 21.

With reference to FIG. 8, the previously mentioned transfer point 46 forsolids and liquids is shown. Solids must be transferred from the trough23 into trough 22 while liquids flow freely in the reverse directionfrom the trough 22 into trough 23. The adjacent trough side walls areagain notched at 61, FIG. 8, to provide a horizontal lip 62 identical tothe previously described lip or edge 60. The rotating scoop 63 forsolids at transfer point 46 and the coacting scavenger plate 64 areidentical in construction and operation to the previously describedelements 49 and 56. This arrangement. FIG. 8, enables the counterpassage of solids from the trough 23 to the trough 22 and liquid fromthe trough 22 to the trough 23 exactly as described previously inconnection with transfer point 45.

FIG. 8 also depicts a somewhat modified scoop and scavenger plate foruse at the solids outlet 43. Outlet 43 must discharge the solids fromtrough 21 at a higher elevation than transfer points 45 and 46 becauseat outlet 43, no liquid is discharged from unit 20. This feature becomesparticularly important where multiple units 20 are employed in a moreelaborate system employing multiple liquids, such as the system of FIG.9 to be described hereinafter. In FIG. 8, a scoop 64a is shown includingessentially flat parallel opposed scoop blades 65 whose tips operateclose to the curved wall of trough 21. Blades 65 are connected by rightangular extensions 66 to a hub 67 which is cross-bolted at 68 to anadjacent rotary shaft 29. Scoop blades 65 may be braced by diagonalbraces 69 as shown. A somewhat modified scavenger plate or scraper 70 ispivotally suspended as at 71 from brace bars 26 and a stop element 72 isprovided on bar 26 to limit downward swinging of scavenger plate 70. Theouter side wall portion 73 of trough 21 is somewhat elevated relative tothe edges of 61 and 62 to assure that no liquid will be discharged atsolids outlet 43. There is therefore a relatively high elevationdischarge of solids from unit 20 as is desirable. A suitable chute 74 orconveyor means or receptacle is provided at the solids outlet of unit20. The general operation of the modified scoop device 64, 64a issimilar to that of scoop device 49. Scoop blades 65 and their side wallportions 75 scoop and elevate the solids from trough 21 and coactingscavenger plate 70 scrapes the solid material from the two sections ofthe scoop and transfers it to outlet chute 74 without allowing anyliquid outlet at this point. The basic feature in the apparatus at thispoint is the elevation of outlet 43. The scoop has been modified forthis purpose. In other respects, the apparatus is essentially the sameas previously described.

An ion exchange system, embodying the present invention, in which solidscirculate continuously through the troughs and never leave, is shown inFIG. 9.

The several units 70 in FIG. 9 are basically the same as the unitdescribed in detail previously and need not be further described indetail. The system shown in FIG. 9 provides for example an arrangementwhereby several distinct liquids may be caused to contact a given solid,without any intermingling of the liquids and while the solids aretransferred from unit-to-unit of the apparatus containing the varioustreatment liquids. In one form, there is an ion exchange treatment inthe unit 70 at the bottom of FIG. 9 followed by a first washing of thesolids, a regenerative treatment at the top of FIG. 9 and a secondwashing, as shown.

In FIG. 9 the continuous path of solids from unit 70 to unit 70 of thesystem is shown by the solid line arrows 76. The counter flow of theparticular liquid in each unit 70 is designated by broken line arrows77. From an inspection of these full line and broken line arrows in FIG.9, it is readily apparent that the particular liquid in each unit 70remains in that unit and is not transferred to a next adjacent unit 70and therefore does not commingle or mix with any other treatment liquidin the entire system. The solids, on the other hand indicated by thefull line arrows, are transferred from unit-to-unit through the entiresystem to receive a separate treatment by a separate liquid flowingcounter thereto in each unit 70. Various like systems can be devisedwith the basic unit 70.

More particularly in FIG. 9, solids enter a first wash unit 70 at 78from an ion exchange unit of the system indicated at 79. There is asolids transfer means 80 at this point having one of the high leveltransfer scoops 75 and associated elements, previously described. Thefirst wash liquid enters the first wash unit 70 as at 81 and flowscounter to the solids in this particular unit. The solids aretransferred at 82 to the next unit 70 at the top of FIG. 9 by anotherone of the previously described typical high level transfer means whichprevents the transfer of liquid while effecting the transfer of solids.The first wash liquid discharges at 83 to a common sump 84 or the like,centrally located in the system.

The solids transferred at 82 discharge onto a short solids conveyor 85carrying the same into a regenerant unit 70 at 86. Regenerant liquidflowing oppositely to the solids enters at 87 and is discharged at 88 inFIG. 9. The solids are again transferred by transfer means 89 to asecond wash unit 70 of the apparatus designated 90 in FIG. 9. The secondwash liquid enters this unit at 91 and is discharged at 92 to the commonsump 84 after flowing counter to the solids in the three troughs of theparticular unit. After the second wash of the solids, they aretransferred at 93 to a conveyor 94 which carries the solids to the ionexchange unit 79. The ion exchange liquid enters this unit 95 anddischarges therefrom at 96. Each discharged liquid at a particular unit70 of the system is controlled by one of the weirs 78 previouslydescribed, FIG. 2. Each unit has within it the previously described lowlevel transfer points to allow transfer in the opposite direction ofboth solids and liquid within a particular unit 70 of the total systemshown in FIG. 9. As stated, the several liquids of the entire systemcannot and do not mix because of the high level transfer means forsolids only between the several units 70.

OPERATION In operation, blades 30 and scoops 31 cooperate to advancesolids and to ensure their intimate contact with the counter-currentliquid. The diametrically opposted positioning of the blade and scoop ofany pair ensure that the most highly compacted regions of the solidsdispersion as produced by the scoops are con tacted by the blades. Itwill be observed that, longitudinally of shaft 29, the dimension ofscoop 31 is larger than the dimension of blade 30 and that, radially ofshaft 29, the dimension of scoop 31 and the dimension of blade 30 areapproximately the same. It has been found that this apparatus multipliesthe efficiency of ion exchange reactions by at least an order ofmagnitude with respect to prior ion exchange apparatus.

Since certain changes may be made in the foregoing disclosure withoutdeparting from the invention hereof,

it is intended that all matter shown in the accompanying drawings orcontained in the foregoing drawings be interpreted in an illustrativeand not in a limiting sense.

What is claimed is:

l. A liquid and solids continuous contact counter flow apparatuscomprising a body portion defining at least a trough, a rotary shaftextending longitudinally through said trough, a plurality of spacedgenerally radial paddles on said shaft collectively forming aninterrupted helical distribution on said shaft, said paddles includingsubstantially flat and substantially curved scoops, said paddles beingarranged as pairs of oppositely radially directed scoops and blades,said scoops, longitudinally of said shaft, being of greater dimensionthan said blades, said scoops and said blades, radially of said shaft,being of approximately equal dimension, each of said scoops beingapproximately hemispherical in cross section with an open top and anopen end.

2. A counter-current contactor for liquid and solids comprising aplurality of side-by-side elongated generally U-shaped substantiallylevel troughs, a plurality of shafts, one each of said shaft extendingrotatably and lengthwise through one each of said troughs, a pluralityof adjustable pitch paddles on each of certain of said shaftscollectively forming an interrupted helix on said each of said certainof said shafts, means to drive said shafts in unison and in the samedirection, lower level transfer rotary scoops connected with certain ofsaid shafts and driven thereby to transfer solids from one of saidtroughs to others of said troughs in said contactor and permittingcounter flow of liquid in and between said troughs, a higher levelsolids discharge rotary scoop connected to certain of said shafts anddriven thereby to lift and discharge solids from said contactor andretaining liquid therein, and a vertically adjustable weir to regulatethe level of liquid in all of said troughs of said contactor, saidpaddles including a plurality of scoops and a plurality of blades, eachof said scoops having inner face portions defining a partially enclosedregion for tumbling said solids and said liquid, each of said bladeshaving a single forward face portion for advancing said solids in onedirection while permitting counter-flow of said liquid, said scoops andsaid blades being mechanically related in a geometrical pattern, saidpaddles being arranged as pairs of oppositely radially directed scoopsand blades.

3. The apparatus of claim 1 wherein longitudinally of said shaft, saidscoops are of greater dimension than said blades.

4. The apparatus of claim 1 wherein radially of said shaft said scoopsand said blades are of approximately equal dimension.

5. The apparatus of claim 1 wherein each as said scoops is approximatelyhemispherical in cross section with an open top and an open end 6. Theapparatus of claim 1 wherein said scoops and said blades are adjustablyconnected to said shafts by cross shafts to which said scoops and saidblades are fixed by lock nuts 7. A counter-current contactor for liquidand solids comprising a plurality of side-by-side elongated generallyU-shaped, substantially level troughs, each of said troughs beingsubstantially equal in length and extending the entire length of saidcontactor, vertical side walls of said troughs being the same height,the two outermost troughs of said plurality extending above said sidewalls, a plurality of shafts, one each of said shafts extendingrotatably and lengthwise through one each of said troughs, said one eachof said shafts being hollow, a plurality of adjustable pitch paddles onsaid one each of said shafts collectively forming an interrupted helixthereon, said paddles including a plurality of blades and a plurality ofscoops, one each of said blades having a flat plate element havingoutwardly diverging side edges and circularly curved outer peripheraledge, one each of said scoops having a cylindrically curved catchportion that is semicircular in crosssection with a flat inner face,each of said blades and said scoops rigidly anchored to an adjustingrod, adjustable screw threaded parts connecting said paddles and saidrotary shaft, lower level transfer rotary scoops including diametricallyopposed reversely curved blades connected to certain of said shafts anddriven thereby to transfer solids from one of said troughs to another ofsaid troughs and permitting counter flow of liquid between said troughs,a higher level solids discharge scoop including diametrically opposedreversely curved blades connected to certain of said shafts and driventhereby to lift and discharge solids from said contactor and retainingliquid therein, a vertically adjustable weir to regulate the level ofliquid in all of said troughs of said contactor, said one each of saidscoops having inner face portions defining a partially enclosed regionfor tumbling said solids and said liquid, said one each of said bladeshaving a single forward face portion for advancing said solids in onedirection while permitting counter-flow of said liquid, said scoops andsaid blades being mechanically related in a geometrical pattern, saidone each of said scoops being of greater dimension than said one of saidblades in a direction longitudinally of said shafts, said one each ofsaid scoops and said one each of said blades being of approximatelyequal dimension in a direction radially of said shafts, said one each ofsaid scoops being approximately hemispherical in cross-section with anopen top and an open end, said paddles being arranged as pairs ofoppositely radially directed scoops and blades.

8. A liquid and solids continuous contact counter flow apparatuscomprising a body portion defining at least a trough, a rotary shaftextending longitudinally through said trough, a plurality of spacedgenerally radial paddles on said shaft collectively forming aninterrupted helical distribution on said shaft, said paddles includingrelatively flat blades and relatively curved scoops, said paddles beingarranged as pairs of oppositely radially directed scoops and blades.

l l i t

1. A liquid and solids continuous contact counter flow apparatuscomprising a body portion defining at least a trough, a rotary shaftextending longitudinally through said trough, a plurality of spacedgenerally radial paddles on said shaft collectively forming aninterrupted helical distribution on said shaft, said paddles includingsubstantially flat and substantially curved scoops, said paddles beingarranged as pairs of oppositely radially directed scoops and blades,said scoops, longitudinally of said shaft, being of greater dimensionThan said blades, said scoops and said blades, radially of said shaft,being of approximately equal dimension, each of said scoops beingapproximately hemispherical in cross section with an open top and anopen end.
 2. A counter-current contactor for liquid and solidscomprising a plurality of side-by-side elongated generally U-shapedsubstantially level troughs, a plurality of shafts, one each of saidshaft extending rotatably and lengthwise through one each of saidtroughs, a plurality of adjustable pitch paddles on each of certain ofsaid shafts collectively forming an interrupted helix on said each ofsaid certain of said shafts, means to drive said shafts in unison and inthe same direction, lower level transfer rotary scoops connected withcertain of said shafts and driven thereby to transfer solids from one ofsaid troughs to others of said troughs in said contactor and permittingcounter flow of liquid in and between said troughs, a higher levelsolids discharge rotary scoop connected to certain of said shafts anddriven thereby to lift and discharge solids from said contactor andretaining liquid therein, and a vertically adjustable weir to regulatethe level of liquid in all of said troughs of said contactor, saidpaddles including a plurality of scoops and a plurality of blades, eachof said scoops having inner face portions defining a partially enclosedregion for tumbling said solids and said liquid, each of said bladeshaving a single forward face portion for advancing said solids in onedirection while permitting counter-flow of said liquid, said scoops andsaid blades being mechanically related in a geometrical pattern, saidpaddles being arranged as pairs of oppositely radially directed scoopsand blades.
 3. The apparatus of claim 1 wherein longitudinally of saidshaft, said scoops are of greater dimension than said blades.
 4. Theapparatus of claim 1 wherein radially of said shaft said scoops and saidblades are of approximately equal dimension.
 5. The apparatus of claim 1wherein each as said scoops is approximately hemispherical in crosssection with an open top and an open end.
 6. The apparatus of claim 1wherein said scoops and said blades are adjustably connected to saidshafts by cross shafts to which said scoops and said blades are fixed bylock nuts.
 7. A counter-current contactor for liquid and solidscomprising a plurality of side-by-side elongated generally U-shaped,substantially level troughs, each of said troughs being substantiallyequal in length and extending the entire length of said contactor,vertical side walls of said troughs being the same height, the twooutermost troughs of said plurality extending above said side walls, aplurality of shafts, one each of said shafts extending rotatably andlengthwise through one each of said troughs, said one each of saidshafts being hollow, a plurality of adjustable pitch paddles on said oneeach of said shafts collectively forming an interrupted helix thereon,said paddles including a plurality of blades and a plurality of scoops,one each of said blades having a flat plate element having outwardlydiverging side edges and circularly curved outer peripheral edge, oneeach of said scoops having a cylindrically curved catch portion that issemicircular in cross-section with a flat inner face, each of saidblades and said scoops rigidly anchored to an adjusting rod, adjustablescrew threaded parts connecting said paddles and said rotary shaft,lower level transfer rotary scoops including diametrically opposedreversely curved blades connected to certain of said shafts and driventhereby to transfer solids from one of said troughs to another of saidtroughs and permitting counter flow of liquid between said troughs, ahigher level solids discharge scoop including diametrically opposedreversely curved blades connected to certain of said shafts and driventhereby to lift and discharge solids from said contactor and retainingliquid therein, a vertically adjustable weir to regulate the level ofliquid in all of said troughs of said contactor, said one each of saidscoops having inner face portions defining a partially enclosed regionfor tumbling said solids and said liquid, said one each of said bladeshaving a single forward face portion for advancing said solids in onedirection while permitting counter-flow of said liquid, said scoops andsaid blades being mechanically related in a geometrical pattern, saidone each of said scoops being of greater dimension than said one of saidblades in a direction longitudinally of said shafts, said one each ofsaid scoops and said one each of said blades being of approximatelyequal dimension in a direction radially of said shafts, said one each ofsaid scoops being approximately hemispherical in cross-section with anopen top and an open end, said paddles being arranged as pairs ofoppositely radially directed scoops and blades.
 8. A LIQUID AND SOLIDSCONTINUOUS CONTACT COUNTER FLOW APPARATUS COMPRISING A BODY PORTIONDEFINING AT LEAST A TROUGH, A ROTARY SHAFT EXTENDING LONGITUDINALLYTHROUGH SAID TROUGH, A PLURALITY OF SPACED GENERALLY RADIAL PADDLES ONSAID SHAFT COLLECTIVELY FORMING AN INTERRUPTED HELICAL DISTRIBUTION ONSAID SHAFT, SAID PADDLES INCLUDING RELATIVELY FLAT BLADES AND